308 AD...

[gaptrick]

Bro in law was sighting in his .308 AR.....

Couldn't use the leadsled like he'd want due to mag interference.

He'D lock back the BCG and chamber a round one at a time. He'd done this 5 or 6 times, then on the next one, he let the BCG go home as usual and... bang.

A common occurabce?

[JimE]

Slam Fire.
Check your ammo for high primers.
It is also possible that he hit the trigger at the right time (accidently) , or the trigger/hammer engagement failed. That is pure speculation on my part.

[evan price]

Floating firing pin.
Soft commercial primers maybe.
High primer maybe.
It happens.

[Sevens]

...and it is a design FEATURE in Stoner rifles that I simply loathe, and I am a not very vocal 0.0001%.

Fun test at home!
Take your average run of the mill 5.56 AR and place one round in a magazine, put the magazine in the rifle and snap the bolt closed with your thumb.

Now eject that round and inspect your primer.

Now, inspect your shorts.

But yes, I completely understand that it's only me and maybe six other people on the planet that -HATE- this. This is okay, I definitely don't care if nobody agrees.

[Brian D.]

On the relatively rare occasion that I am loading/unloading a gun inside the house, I always pick a muzzle direction with a "bullet stop", some item thick enough that a round won't sail through it. My spare bedroom's closet is the best place to do that.

It's done more for safety while charging a firearm as opposed to clearing one. Mechanical devices can fail, albeit rarely.

[gaptrick]

Thanks for the replies. It a Rock River rifle with no issues up til now. He's peed because for all that money he'll always have that in the back of his mind. He did say the crater it left 5 feet in front of him was impressive.

I don't know if he was shooting store boughts or reloads (his). I'll find out.

How high would you think a primer would need to be that it would lend itself to this mishap?

[gaptrick]

The trouble maker is on the LEFT

[Sevens]

With a NATO head stamp that should be a mil-spec primer.

It's natural for your brother to be angry but the fact is that he shares the blame. Try to be nice when you break that news to him. If the rifle and the ammo is proper and well-functioning, that WILL NOT HAPPEN when the round is stripped from a magazine as it was designed to do.

You both ought to know simply from owning and using semiautomatic handguns that it's a BAD IDEA and the work of a novice to drop rounds in the chamber and slam a slide or a bolt on top of them. Do that with a 1911 and you eventually get to learn the art of 1911 extractor tuning.

Thankfully he was on a range when he ND'd his rifle and it wasn't pointed in Brian D's closet.

[Brian D.]

Thankfully he was on a range when he ND'd his rifle and it wasn't pointed in Brian D's closet.

The ( most all non essential) items in Brian D.'s spare bedroom closet would collectively stop a bullet, maybe I didn't make that clear. Plus, the subfloor beneath contains an inch or more of poured concrete. I know that from bolting down my gun safe.

It's not like I'm hoping to do that, just being as careful as circumstances allow. The potential for hearing loss alone should keep us all behaving on the careful side.

[calvin56]

With a NATO head stamp that should be a mil-spec primer.

It's natural for your brother to be angry but the fact is that he shares the blame. Try to be nice when you break that news to him. If the rifle and the ammo is proper and well-functioning, that WILL NOT HAPPEN when the round is stripped from a magazine as it was designed to do.

You both ought to know simply from owning and using semiautomatic handguns that it's a BAD IDEA and the work of a novice to drop rounds in the chamber and slam a slide or a bolt on top of them. Do that with a 1911 and you eventually get to learn the art of 1911 extractor tuning.

Thankfully he was on a range when he ND'd his rifle and it wasn't pointed in Brian D's closet.

You hit the nail on the head. This was a negligent discharge not accidental. If you use a firearm in a way it wasn't intended you will eventually have problems. With no friction from the mag the bolt group flew forward giving the firing pin enough inertia to set the primer off.

[CCIman]

This is a user issue. He needs to just not do it again and learn from the experience. As far as common occurence - no.

They do make 5, 10, 20 round mags that may work in the sled. Stripping off the mag is best way.

There is a way to gently let the bolt down then FORWARD ASSIST it into place, so as to not wake the paper targets or scare the pigs. That is where the forward assit can come in handy.

Thanks for the replies. It a Rock River rifle with no issues up til now. He's peed because for all that money he'll always have that in the back of his mind. He did say the crater it left 5 feet in front of him was impressive.

I don't know if he was shooting store boughts or reloads (his). I'll find out.

How high would you think a primer would need to be that it would lend itself to this mishap?

[CCIman]

He may want to check the firing pin- they do make "upgraded" or "enhanced" pins especially for the 7.62x39 market to improve ignition in hard primers in steel case.

These pins are normal length AR pins but the shoulder collar was slightly turned to make the pin protrude further out.